Re: #f vs. '() vs. nil

Per Bothner (bothner@deneb.cygnus.com)
Fri, 06 Sep 1996 12:54:43 -0700

> It is effectively UNSPECIFIED, whether or not the empty list is the false
> object or not.

>From R4RS, as published in Lisp Pointers IV:3:

6.1 Booleans

Except for #f, all standard Scheme values, including #t, pairs,
the empty list ....

Note: In some implementations the empty list counts as false,
contrary to the above. ...

This does seems to be contradicted by Clinger's pre-amble (page i).

In any case, both IEEE Scheme and R5RS require
that () is not #t, so we should aim for that.

--Per Bothner
Cygnus Support bothner@cygnus.com